Shock absorbers or linear decelerators are often used on industrial equipment that requires the shock absorber or linear decelerator to cycle at very high rates. For instance, in the blow molding industry, plastic bottles are made by placing heated cylindrical blanks into a mold and inserting pressurized air into the blanks to stretch the mold radially to form to the mold. While the pressurization of the blank is occurring, a striker is inserted into the blank to engage the bottom of the blank and stretch the blank vertically. Shock absorbers or linear decelerators are utilized to cushion the impact of the vertical strikers. These blow molding machines may produce up to 20,000 to 40,000 bottles per hour, and therefore, the cycling rates of the striker and the wear on the shock absorbers is great. Such cycling and wear typically requires that the shock absorbers be replaced or maintained on a regular basis.
Previous designs have mounted the shock absorber 11 in a manner which makes maintaining the shock absorber 11 difficult. As seen in FIG. 1, the shock absorber 11 has a housing 13 with a piston rod 15 extending therefrom. The housing 15 of the shock absorber 11 has threads on its outer periphery and is threaded into a threaded bore 17 of a mount 19 of an industrial machine. The threaded bore 17 has a stepped diameter which forms a shoulder 21 in the mount 19. The shock absorber housing 13 is threaded into the bore 17 such that the end of the housing 13 abuts the shoulder 21 of the mount 19, and the piston rod 15 extends outwardly from the housing 13. A lock screw 23 is threaded into a threaded aperture 25 extending from the side of the mount 19 at an angle substantially perpendicular to the longitudinal axis of the shock absorber 11. The lock screw 23 engages the outer threads of the housing 13 of the shock absorber 11 in order to retain the shock absorber 11 in a predetermined position.
When the shock absorber 11 requires maintenance, the mount 19 is removed from a fixture 25 of an industrial machine, such as a blow molding machine (not shown). The lock screw 23 is unthreaded from engagement of the housing 13 of the shock absorber 11 so that the housing 13 may be unthreaded from the mount 19. Maintenance may then be performed on the shock absorber 11, and the shock absorber 11 may be threaded back into the mount 19. However, the lock screw 23 often damages the threads of the shock absorber housing 13 thereby making it difficult to thread the shock absorber housing 13 out of and into the mount 19. In some instances, the shock absorber housing 13 may not thread all the way into the bore of the mount 19 such that the shock absorber housing 13 does not engage the shoulder 21 of the mount 19. This may occur without the mechanic realizing that the shock absorber housing 13 is not threaded all the way into the bore. If this occurs and the shock absorber 11 and the mount 19 are placed back into the fixture 25, the piston rod 15 will not be in its proper position, thereby affecting the stroke length of the shock absorber 11. This, in turn, may affect the operation of the machine. Such shortcomings create an increase in the maintenance frequency of the shock absorbers 11 thereby creating an inefficiency that is undesirable in an industrial environment.
It is desirable to provide a quick change shock absorber that allows for the quick and easy maintenance of a high-cycling shock absorber while ensuring for the accuracy of the set up of the shock absorber.